aaudio:  validate audio data format

Also lots of minor cleanup
Fix underscores in some headers
Refactor getTimestamp()

Bug: 34127069
Bug: 38227780
Test: CTS test_aaudio.cpp
Change-Id: I6fdb50eb00a41688df871018ced91d5f5f055f8a
Signed-off-by: Phil Burk <philburk@google.com>
23 files changed